Liquid level gauge



Aug. 19, 1952 P. H. BiscoE LIQUID LEVEL GAUGE 2 SHEETS-SHEET l Filed Jan. 25, 1948 41 v E wwf/MGM AT'roRNEY Aug. 19, 1952 P. H. 'BlscoE l 2,4607225 y LIQUID LEVEL GAUGE Filed Jan. 25, 194s 2 SHEETS- Smm 2 ATTORNEY Patented Aug. 19, 1952 LIQUID LEVEL GAUGE Percival H. Biscoe, Jacksonville, Fla., assignor to Saf-T-Visi Gauge Corporation, a corporation of Florida Application January 23, 1948, Serial No. 3,977

3 Claims.

The present application relates to the subject matter of copending applications Serial No. 714,964, filed December` 9, 1946, now abandoned, and Serial No. 761,487, filed July 17, 1947, and pertains to an invention relating to liquid level indicators or gauges of the sight tube type.

The ordinary liquid gauge of the type referred to for measuring the height of liquid in a vessel under substantially atmospheric pressure, such as that employed in connection with a fuel oil tank, comprises generally a vertically mounted transparent frangible sight tube sealed or packed into a pipe fitting connected to said vessel below the level of the liquid therein. Upon accidental breakage of this sight tube,v the liquid from the vessel will escape through the fractured tube before the matter has been attended to, as, for example, by the closing of a hand valve in the pipe fitting.

Furthermore, in such conventional liquid gauges, the sight tube must be packed or sealed during the operation of installing the gauge in position, so that this tube may be fractured by the installer during such operation, as a result of the application of excessive packing or sealing pressure.

One object of the present invention is to provide a new and improved liquid gauge having a safety valve which closes automatically by positive action upon fracture of the sight tube and which thereby prevents the escape of liquid from the vessel through said tube.

Another object is to provide a new and improved safety liquid gauge of the self-closing character above referred to, which has valve oating features assuring the proper seating of the valve member in closed position, which is positive in its closing action, which is inexpensive of construction and reliable in operation, which is of unit assembly construction with its sight tube prepacked or presealed in position into a safety valve tting, so that the possibility of applying destructive sealing or packing pressure to the sight tube during the mounting of the gauge is avoided, which can be easily applied to existing gauge mounting installations with minimum of pipe fitting operations, which can be quickly, easily and expeditiously removed from its pipeline mounting, which is constructed to minimize the clogging and the collection of dirt and grease around the safety valve seat during normal operations, sothat effective, automatic and tight closing of the safety valve is assured when circumstances require it and which lends itself to quick and effective cleaning with minimum of manipulation when removed from its mounting.

Various other objects of the invention Will be apparent from the following description and by the inspection of the accompanying drawings, in

which- Fig. 1 is a side elevation of a form of safety liquid gauge embodying the present invention and shown in installed o-perative position with respect to a pipeline or connection leading from the lower section'of a tank or Vessel; y

Fig. 2 is a longitudinal section of the safety liquid gauge of Fig. 1 taken along lines 2-2 of Fig. 1 but on a larger scale and shows said gauge in operative position before fracture of the sight tube and while the valve member is forced off its seat, to maintain communication between the vessel or tank whose liquid level is being measured and the interior of said sight tube;

Fig. 3 is a longitudinal section of the safety liquid gauge taken along the lines 2 2 of Fig. 1 and shows said gauge after the sight tube has been fractured accidentally and the safety valve automatically closed to block communication with the pipeline or connection leading from the tank or vessel;

Fig. 4 is a perspective of the liquid gauge per se shown ask a self -contained unit prior to its being mounted into operative position into a pipeline or connection; Y

Fig. 5 is a side elevation of the liquid gauge unit similar to that of Fig. 1 but shown mounted into a spigot connected toa drum or tank; and

Fig. 6 is a longitudinal section of another form ofl liquid safety gauge embodying the present invention and shown in intact operative condition.

Referring to Figs. 1 to 4 of the drawings, there is shown a conventional tank, vessel, drum or receptacle I0 maintained under substantially atmospheric pressure and adapted to hold the liquid Whose level is to be measured by the gauge of the present invention. This tank I0 may serve for v anysuitable purpose where a liquid container is required, as for example, as a liquid fuel tank and has a pipeline or connection I I from its lower sectioncleading to a distant point where the liquid is to be used, treated or consumed. For example, this connection I I may lead to a burner or stove in the case where the vessel I0 serves as a liquid fuel tank and may constitute as shown a pipe I2 screwed into said tank, a hand valve I 3 shown as a standard globe valve screwed to said pipe I2, a T-itting I4 having its axial inlet branch connected into the outlet side of said hand valve through a pipe-nipple l5 and its axial outlet branch screwed into a pipe I6 leading to a remote point as indicated.

The tank installation with its pipe connection vliquid gauge into the lateral branch or Outlet I1 of the T-fitting I6.

The liquid level gauge unit of the present invention shown in Figs. 1 to 4 comprises a frangible transparent sight tube 2 I, which as far as certain aspects of the invention are concerned, may be of any material suitable for the purpose, but which in the specific form shown is of plastic material of a type which lends itself readily to pipe threading. The lower end of this sight tube 2I has an external pipe thread I9 and is screwed into the outlet end of a unitary or one-piece tubular valve fitting 22 having its inlet end constructed for connection to the pipeline or connection II. This fitting 22 is made of any suitable metal, such as brass or stainless steel and has an upper cup-like internally pipe-threaded section 23 forsealably receiving the lower end of the sight tubeZIand a lower valve casing section 24 defining a valve chamber 25 for a mo'vable spring loaded Asafety valve member 2,6. A transverse wall 2l between the two tting sections 23 andrZ-defines a stop shoulder for the lower. end of the sight Jtube 2l and is apertured to form a valve passage or port betweenthe valve chamber 25 and the interior of the said sight tube. The lower edge of this transverse wall 2l is desirably lapped or otherwise machined tov forman annular valve seat 3l of small depth conforming in transverse curvature to that of the valve member 26.

The lower endof the sight tube 2I is screwed into the upper cup-like fitting section 23 and is sealed therein by meansnof, v.a thread ller 33 such as that ordinarily employed for sealing threaded pipe joints. This ller while in plastic condition is applied to the threads of the sight tube 2| before said tube is screwed into the tting 22 and solidifies to forma firm water-tight joint.

The valve member 26 is desirably in the form of a spherical ball and is urged towards closure'position against its valveseat 3l by meansof a coilspring 34in the valve chamber ,25. This coil spring 34 has its upper section 35 tapered to prevent it from telescoping into its lower section and. reduced in pitch to form a substantially horizontal end convolution on which the ball can rmly, rest without being cocked. The lower end of 4this coilspring 3l!y rests onan outer tranverse end wall 35 provided with an aperture 3l to maintain communication between the main passage of the T-tting IA and the valve chamber 25.

`The lower section of the valve tting 22 is provided externally with a pipe thread 38 for connection into the lateral branch or outlet I 'I of the Tfntting I4 and may be sealed therein by a suitable sealing composition 39 similar to that employed to seal the sight tube 2I into the valve fitting 22. p

The valve fitting 22 is built to retain permanentlynthe ball valve member 26 and the coil spring 34 therein and to form therewith a selfcontained unit. To that end, the fitting 22 is constructed from solid stock which is bored from both ends to form the upper cup section 23 and the lower valve casing section 24 and to define a vsolid transverse wall between said sections. This transverse, wall is then drilled or apertured and lapped Vor machined to form the transverse ported wall 21 with its valve seat 3l. The valve lower lip or skirt constituting an axial extension of the peripheral wall of said fitting. The ball valve member 26 arid the spring 34 are then inserted into the fitting through the lower open end thereof and the end lip forged or crimped inwardly by a suitable die forging tool to form the aperture `.end wall 350i .the tting22 and to retain said lvalve elements 26, 34 permanently in said fitting.

`The valve member 25 is urged towards the valve seat 3l by the coil spring 34 but is normally crowded out of contact with said valve seat and into open position by means of a column member 40 extending vbetween said Valve member and the upper end of the sight tube 2I. This column member 40 is desirably so constructed as to be rigid or unyieldable when subjected to endwise compressive forces encountered in the operation of the gauge and is preferably in the simple form of a straight cylindricalrod, as shown, although as far yas certain aspects of theginvention are concerned, it may be in the'form of a collapsible column maintained against collapse by the sight tube 2I.in intact condition. For example, as far as certain aspects of the invention are concerned, l

thelcolumn member 4U lmay take the form of a plurality of balls, as shown and described in the aforesaid copending,Y application Serial No. 761,487.

To provide abearing surface for the upper end of the, rod 43, there is threaded on to the upper end of the sight tube 2l a c-ap 4I, desirably of metal. This cap 4I desirably has its end wall in-v ternally tapered or chamfered to denne a bearing surface Vl2 at its central deepest part for the upper end of the rod 40. This chamfering may be formed'by the very drilling or boring tool employed to hollow out the stock block from which the cap 4I is produced andthe resulting taper serves to maintain the rod 48 in central position with respectvto the sight tube 2| and with respect to the valve passage or port 36 vthrough which it passes.

The rod 40 is long enough so that it extends between the cap 4I and the valve member 26 in olfseated position of said valve member and is small enough in diameter to pass through the valve passage or port 30 with enough clearance to affordl free communication between the valve chamber 25 and the interior of the sight tube 2l through said passage.

This rod 4B bears at its lower end against the valve member 26 to crowd said valve member oif its seat 3 I, and vis desirably conca-ved at this lower end inv conformance with the spherical curvature of said valve member to form a seat for said valve member and to avoid thereby lateral displacement of said rod relative to said valve member during normal conditions.v

The rod 13.0 is in oating relationship to the valve member 26 Aand the cap 4I, That is,v the rod 40 is free or loose from attachment at its ends to the valve member 26 and thel cap 4I. This rod floating feature permits inexpensive construction, permits easy assembly and permits the cap 5I to be screwed into place with minimum turning of the rod 30, and therefore with minimum scarring of the surface of the valve member 2 6. Furthermore, this floating rod feature has the important advantage of permitting the valve member 25 toself-align itself into proper seatingpposition, withoutthe confining influence of the rod 40, upon breakage of the sight tube 2 l The rod 4G may have graduations clearly visible through the transparent sight tube 2l to indicatel liquid level and serves not only to maintain the valve member 26 normally' away from its seat 3| in open position'but has the effect of rendering the liquid surface insaid sight tube more visible by the refractive eifectfcreated on'the liquid- Aimmersedpart of said rod. Y

The-'sight tube 2| hasa vent hole 44 below the cap 4| to maintain the interior of vsaid tube under substantially atmospheric pressure. If the tank I0 contains a liquid whosel vapors should not be made to escape into the atmosphere for some reason or other, the -vent hole 44 may be connected'to the `vapor space of said tank by a capillary tube of desirably flexibleor yieldable characteristics.

In assembling the gauge at the factory, after the sight tube 2| has been yscrewed and sealed into the completed valve enclosing fitting 22', the rod YIl!) is inserted into vsaid tube through the upper open end thereof. At this stage of assembly, the valve member 2Blwill be pressed against its seat 3| by the spring 34 and the upper end of said rod will project outwardly beyond the upper open, end of the sight tube 2|. The cap 4| is then screwed on to theupper end of thevsight tube 2|. This operation will force the rod 40 endwise Vagainst the valve member 26 and vwill move said valve `member off its seat 3l in open position as shown in Fig. 2. The gauge so assembled at tlriefactory'into` a self-contained unit as shown in Fig. 4 may be .stored and shipped as :Y

such and is ready for mounting into a pipeline or connection leading from any tank or vessel whose liquid level is to be measured.

Since the sight tube 2 I' has been presealed into the fitting 22 at the factory by expert hands and has been presumably factory inspected for possible fractures, there is no necessity for applying sealing or packing pressure t0 said sight tube hand valve |3-is closed. The arrangement ofthe gauge mounting thread 38 aboutvand concentric with the longitudinal axis of the gauge yunit 2D permits this easy mounting of the gauge in operative position.

Upon the opening of the hand valve I3, the gauge unit will be ready for immediateoperation. The liquid from the tankl will then'flow past the open valve i3 and into the sight tube 2| until it reaches the level of the liquid in. said tank l0. l l

In case the sight tube 2| should be fractured or broken while in operation, as shown in Fig- 3, the cap lil will no longer bear down on therodAB, so that the spring 34 will immediately push. the valve into closed position against the valve seat 3|. IThe flow of liquid through the valve passage is thereby checked as shown in Fig. 3, so thatescape of liquid from the tank l0 through the fractured tube 2| is prevented. Thehand Wheel |3 can then be closed and the brokenl gauge unit easily replaced by a new one.

Since the valve seat 3| is intended to cooperate with the ball valve member 26, it may be of small area so that in operation it does not lend itself so readily to the adherence and accumulation of dirt thereon. The valve is therefore not aptl to become clogged in operation or its valve seat 3| to collect sufiicient dirty or grease thereon to in'- terfere with effective closing of thevalve when the sighttube 2| isaccidentally broken. Moreover, even if dirt or grease should collect on the valve seat 3 the spring 34 will, nevertheless, push the ball 216 effectively against said valve seat into rm closed Iposition. Because of the small area presented by the valve seat 3|, the pressureper unit area exerted by the spring 34 against said seat upon breakage of the sight tube will be comparatively high and will therefore assure effective closing of the valve, in spite of any accumulation of dirt or grease on said valve seat.

If it is desired to clean the safety valve part of the 'gauge unit 20 after a period Vof use, all that is necessary is to unscrew the gauge unit from'the T-tting I4, dip the valve fitting 22 into a body of water or cleansing liquid and agitate the fitting therein.

The gauge unit 20 as'shown in Fig, 4. may be installed into a pipeline such as that shown in Figs. l to 3 or may be installed into a spigot 45 connected to a drum as shown in Fig. V5. Thecas` ing of the spigot may be providedat its top, ahead of its valve plug `with* a tapped' hole into which the valve fitting V2.2'of the gauge unit 20 may be screwed in the installation of said gaugeunit. Provision for this tapped hole may be made in the manufacture of the spigot, as shown, or if it is desired to installthe gauge unit in anexisting spigot line installation containing no provision for mounting such a gauge unit, the spigot may be tapped in situ toreceive the gauge unit.

Theinstallation of the gauge unit'20 maybe made even .in vcases where the pipeline leading from a tank or vessel does not haverany 'provision for mounting such a gauge unit. The only' re-r quirement necessary to provide for the installation of such a gauge' unit is to drill and tap a hole inthe pipeline. l

In the construction of'Figs.l to 5, the sight tube 2| has been shown of plastic material of the type which lends itself to threading, so that the lower end may be screwed into the valve tting 22 and theupper end screwed into the cap 4|. However, ifthe sight tube 2| is made of'glass, it can rial, embracing said lower tube end and seatedon the upperend of the upper cup1ikesection-23a of said fitting. Avgland or compressionnutil' is screwed over said cup-like fitting section 23a andbears through a washerv52 against the packv ing ring to attach sealably the sight tube t0 the valve fitting 22a. p I

The stuffing box may be of the external type; as shown, with the gland 5| provided with an annular flange 53 internally threaded and screwed over the external thread of the cup-like fitting section 23a or may be of the internal type Where-` in the bore of the upper cup-like section of the valvefitting'is larger than the external diam'- eter of the sight tube 2| a and the packing.ring embracing said sight tube is contained snugly in said section. Such a cup-like section would be internally threaded and a gland in the form of an apertured externally threaded disc would be screwed into the interior of said cup-like section against the packing ring. The gland disc might have a pair of diametrically located slots for receiving a turning tool, such as a spanner wrench.

`The upper end of the glass sight tube 2m may beclosed by a closure 54 constituting an end Wall integral with the side walls thereof and desirably domed or bevelled, as shown, to afford the necessary taper to center the rod 40 in said tube and may be vented through an opening Ma.

'Thetting 22a with its permanently enclosed spring-loaded valve is similar in all respects to the fitting 22 described in connection with the form of -the invention in Figs, 1 to 5, except for the provisions by which the lower unscrewed end of the sight tube 2m may be packed and sealed therein. The operation of the form of gauge unit shown in Fig. 6 is exactly the same as that already indicated in connection with the form of the invention'shown-in Figs. l to 5. v

While the invention has been described with particular reference to specic embodiments, it is to be understood that it is not to be limited thereto but is to be construed broadly and restricted solely by the scope of the appended claims.

What isclaimed is:

1.1 In a liquid level gauge, a sight tube, and an automatic safety valve secured to` one end of said tube-for controlling communication with the interior of said tube through said end and forming a self-contained unit with said tube, said device comprising a unitary tting having at one end a cup section sealably receiving one end of said sight tube, and having at its ther end a tubular valve casing section coaxial with said cup section, Asaid tting having a transverse wall between its sections integral with said sections and apertured to form a valve passage, said transverse wall defining a seat on its valve casing side, means forming an outer transverse apertured end wall for said valve casing section, a ball valve member in said casing section, a coil spring in saidcasing section bearing against said outer end wall and urging said valve member towards said seat, said end wall serving to retain said ball valve member and said coil spring in said valve casing section, said fitting, said end wall, said ball valve member and said coil spring forming a self-contained unit mountable as such with respect to said sight tube,v and a valve unseating column means extending through said tube in floating relationship to said valve member and bearing at one end against said valve member to hold said valve member away from its seat against the action of said coil spring and bearing at the other end against an abutment, said column means being held in valve opening position by said tube while said tube is intact and being 'operable automatically upon breakage of said tube `to release said valve member for closing movement under the action of said coil spring,Y and means for attaching said tting to a vessel-f4 connection including a screw member having an attaching thread coaxial with said sight tube.

2. In a liquid level gauge of the atmospheric type,the combination comprising a sight tube having a closure at one end, and an automatic member movable towards and away vfrom said valve seat, and a spring urging said ball valve member towards said seat, a rod extending through said tube and having one end bearing against said closure and the other end crowding said ball valve member off its seat in open position against the action of said coil spring, said rod being free from fixed attachment;v to said ball valve member and t0 said tube closure, said tube closure being internally bevelled to form a recess tapering towards its outer end to center said rod with respect to said tube at the end where it engages said closure, and means for attaching said tting to a vessel connection including a screw member having an attaching" thread coaxial with said sight tube.

3. In a liquidv level gauge of the atmospheric j having at One end a cup section sealably receiv- "l ing one end of said sight tube, and having at lts other end a tubular valve casingv section coaxial with said cup section and externally threaded coaxially with respect to said sight tube for screw attachment to a valve connection, said tting having a transverse wall between its sections integral with said sections and apertured to form a valve passage, said transverse wall dening a seat on its valve casing side around said valve passage, means forming an outer transverse apertured end wall for said valvel casing section, a ball valve member in said casing section, a coil spring in said casing section bearing against said outer end wall and urging said valve member towards said seat, said end wall serving to retain said ball valve member and said coil spring in said valve casing section, said tting, said end wall, said ball valve member and said coil spring forming a self-contained unit mountable as such with respect to said sight tube, and a rod extending through said tube and having one end bearing against said closure and the other end crowding said ball valve member oi it seat in open -position against the action of said coil spring, said rod having oating engagement free fromsattachment at both ends with said closure and said ball valve member respectively.

PERCIVAL H. BISCOE.

REFERENCES CITED The` following referencesare of record in the leof'this patent:

*I UNITED STATES PATENTS 

